MINISTRY OF EDUCATION & TRAINING

MINISTRY OF HEALTH

HANOI MEDICAL UNIVERSITY

BUI SONG HUONG

STUDY ON THE RELATIONSHIP BETWEEN
ANTINUCLEOSOME AND ANTI-C1q
ANTIBODIES WITH DISEASE ACTIVITY AND
RENAL DAMAGE IN SYSTEMIC LUPUS
ERYTHEMATOSUS IN CHILDREN
Specialized : Pediatrics
Code
: 62720135

SUMMARY OF DOCTORAL THESIS

HANOI - 2019


Research completed in
HANOI MEDICAL UNIVERSITY
Scientific supervisors
Assoc. Prof. Ph.D Le Thi Minh Huong
Ph.D Tran Thị Chi Mai

Scientific reviewer 1:
Scientific reviewer 2:
Scientific reviewer 3:

Research and Practice, 1, 9-15.


1
ABBREVIATIONS
AC1qAb

Anti-C1q antibody

Anti-dsDNA Anti-double stranded DNA antibody
AnuAb

Anti-nucleosome antibodies

AUC

Area under the ROC curve

GFR

Glomerular filtration rate

LN

Lupus nephritis

PCU

Protein/creatinin urinary ratio



2
gold standard for accurately assessing renal histological lesions
however there are contraindications and limitations.
Finding an autoantibody that can show disease activity and
kidney damage is extremely significant by practical value,
convenience and safe. The anti-nucleosome antibody (AnuAb) and
anti-C1q antibody (AC1qAb) are currently focused on by researchers
about the value in assessing disease activity and renal damage, which
may be superior to anti-dsDNA. However, the values of these two
autoantibodies are not yet confirmed and need further study on
different subjects, different geographical regions. Research on the
SLE in children is limited, especially in Vietnam, so this issue needs
to be further explored to improve the assessment and monitoring of
SLE activity even so effectiveness of treatment.
To having a better understanding of the characteristics of
AnuAb and AC1qAb in assessing disease activity and kidney damage
in SLE, we decide to reseach the topic: “Study on the relationship
between antinucleosome and C1q antibodies with disease activity
and kidney damage in pediatric systemic lupus erythematosus” for
the following purposes:
1. Describe some clinical and laboratory characteristics of
systemic Lupus erythematosus in children.
2. Analysis the association between antinucleosome and antiC1q antibodies with disease activity of systemic lupus
erythematosus according to SLEDAI score.
3. Evaluate the association between antinucleosome and antiC1q antibodies with kidney damage in systemic lupus
erythematosus.


3

immune pathways in Lupus which are disorders of programmed cell
death, reducing ability to clean up dead cells and activated T and B
lymphocyte abnormalities, thereby producing autoantibodies. Lupus
pathogenesis is related to many cells and molecules as well as
congenital and acquired immune responses. Autoantibodies may
appear for many years before the onset of clinics. Recently, some
autoantibodies have found that play a major role in SLE
pathophysiology.
Nucleosomes are the basic units of chromosomes playing an
important role in SLE. Programmed cell death releases nuclear
fragments that increase circulating nucleosomes which are altered
and escaped from the normal cleaning process, so leading to increase
expression of nucleosomes to the immune system. Modified
nucleosomes activate nucleosome-specific self-reactive T cells then
stimulate B cells produce AnuAb. The immune complex nucleosomeAnuAb attaches to molecules in the basal membrane of the skin and
kidneys such as heparin sulphate, lamin, collagen 4 or AnuAb is
carried directly to the cross-reactive molecule in the basement
membrane as the alkaline-actinin to organize pathological injury.
C1q is the first component in the complementary activating
chain, stimulates phagocytosis cleaning dead cells, prevents T cell
proliferation, inhibits activation of plasmacytoid dendritic cells,
prevents the production of IFN and inflammatory cytokines. That
plays protecting and inhibiting the immune response against Lupus.
AC1qAb can alter the physiological role of C1q by occupying
important positions associated with C1q receptors, prevent the


5
cleaning process of programmed cells and immun complex leading to
exis immun complex, fixe in the organization and cause organ

Therefore, scientists still try to find new immunological
markers related to the disease activity to identify more
accurately, more sensitive and quickly.
1.4. Lupus nephritis
In SLE, kidneys are the most common, early and severe
organ, especially in children accounting for 37-82%. Lupus nephritis
(LN) may appear in the first year but usually occur in the first 5 years
after diagnosis of SLE. The gold standard is kidney biopsy that
indicates glomerulonephritis mediating by immune complex. Early
diagnosis and treatment of LN is very important to improve survival
in LN patients so it is necessary to identify biomarkers that can
predict the development of LN in SLE.
1.5. Role of anti-nucleosome and anti-C1q antibodies in Lupus
Many autoantibodies have been found in SLE patients but
only some of them have clinical significance. No biological marker
accurately measures the SLE disease activity. Anti-dsDNA has been
widely used in diagnosis, monitoring of disease activity and
assessment of kidney damage during the past time but also revealed
limitations.
Although there have been many reports of AnuAb and aCqA
over the past time, most studies in adults, moreover results are
conflict due to heterogeneous clinical characteristics of SLE. Many
studies have shown that AnuAb is valuable in SLE diagnosis and
related to disease activity level, even the author has suggested using


7
AnuA instead in case of negative Anti-dsDNA. To avoid repeated

kidney biopsies, biomarkers are used to assess kidney damages.


disease history, clinical

manifestations, assessment of disease activity on the SLEDAI scale
for the first time (T0) admission to hospital and was diagnosed SLE
and taken to study, the second time (T3) about 3 months and the third
time (T6) about 6 months after the first time.
- Laboratory was evaluated 3 times at T0, T3, T6 and at the same
time SLEDAI score for hematological tests (full blood count, urinary
sediment), biochemical tests (ure, creatinine, AST, ALT, protein,
albumin, C3, C4 serum concentrations, urine protein and creatinine
levels), quantification of antinuclear antibody, Anti-dsDNA, AnuAb,
AC1qAb.
- Collect data, assess and discuss symptoms with renal and
immuno experts.
2.4. Location and time of study
- SLE patients were examined and treated at the Kidney-Dialysis
Department and Immunology-Allergy-Arthritis Department, National
Children’s Hospital from January 2015 to December 2017.
- Research tests: blood formula tests, biochemical tests,
quantitative antibody tests (AnuAb and AC1qAb) are made in
Hematology and Biochemistry Department in Vietnam National
Children’s Hospital. These laboratories have been accredited with
ISO standards.
2.5. Data processing
The data were processed by STATA 14 software.
2.6. Ethics Research
This is a descriptive, non-intervention study. The research subjects




125
100%

The most common are children over 10 years old (63,2%),
children under 5 years of age are rare (4%).
Table 3.2: Clinical characteristics according to LN and
non-LN groups
Clinical characteristics
Butterfly rash
Discoid
Photosensitivity
Oral ulcer
Alopecia
Arthritis
Fever

LN
Non-LN
n = 99 (100%) n = 26 (100%)
57
13
(57,6)
(50)
3
3
(3)
(11,5)
27
6

21
2
0,16
(21,2)
(7,7)
7
4
Neurologic disorder
0,24
(7)
(15,4)
Common clinical symptoms in both LN and non-LN groups
are butterfly rash, arthritis and fever. The rate of LN in SLE is
99/125, accounting for 79,2%. The non-LN group had a higher rate
of fever than LN group, the difference was statistically significant
with p < 0,05.
Table 3.3: Clinical characteristics of Lupus nephritis group
Serositis

Clinical characteristics

N (n = 99)

% (100 %)

Edema

58

58,6

34
34,3
Decreased serum protein
43
43,4
Decreased serum Albumin
48
48,5
Urinary red blood cells
60
60,6
Urinary white blood cells
68
68,7
Urinary casts
18
18,2
PCU> 200 mg/mmol
72
72,7
Nephrotic syndrom
44
44,4
GFR < 90
40
40,4
The common paraclinical disorders are increased serum


11

98

0,008

44

12

0,032

39

16

0,016

78

0,0000

28

8

0,216

14

10


AnuAb
AC1qAb
Anti-dsDNA

SLEDAI T0
SLEDAI ≤ 10
SLEDAI > 10
60,3
334,1
(7,5-6888,1)
5,3

(5,7-8200)
16,6

(1,7-19)
70,1

(0,2-992,2)
189,45

p
0,014

Table 3.8: Relationship between the concentration of antibodies
Antibody T3

and SLEDAI level at T6 (n = 72)


13

Kháng thể T6
AnuAb

SLEDAI T6
SLEDAI ≤ 10
SLEDAI > 10
35,5
333,95

AC1qAb
Anti-dsDNA

2,6 – 4391,4
5,6

32,4 – 5494,4
25,25

0,8 – 233,7
43,15

3,6 – 138,6

0,417
0,289

0,002
0,000
0,001

SLEDAI
T3
r
p
0,328
0,262
0,31

0,004
0,023
0,007

T6
r

p

0,372
0,429
0,507

0,001
0,000

13 (50)

0,001

Anti-dsDNA Pos

83(83,84)

20(76,92)

0,41

Dicreased C3

94 (94,95)

19 (73,08)

0,0008

Dicreased C4

92 (92,93)

21 (80,77)

0,061

Immunology marker


(2,6-4391,4)

7,4

5

(0,8-233,7)

(1,9-12,4)

54,2

89,8

(2,1-4762,2)

(3,8-422,3)

0,92

1

(0,14-1,82)

(0,563-1,66)

0,15

0,213


Table 3.12: Subclinical manifestations of kidney damage
group III and IV
Manifestation

Group III

Group IV

n=22

n=28

p

(100%)
(100%)
Increased serum creatinine
5(22,7)
18(64,3)
0,003
GFR < 90
6(27,3)
19(69,7)
0,004
PCU >200 mg/mmol
16(72,7)
27(96,4)
0,023
Urinary red blood cells
10(45,5)

(19,3-8200)
18,9

(5,7-1200)
14

(2,4-992,2)

(0,2-600)
150,5

157,35

Anti-dsDNA

(0,1-4200)

p
0,092
0,39

(0,4-

0,784

5153,7)

Median concentrations of antibodies of LN group III and IV
do not different significantly.
Table 3.14: Correlation between antibody concentrations and


-0,25

0,09

Anti-dsDNA

0,09

0,56

-0,01

0,94

Antibody concentrations are not correlated with the chronic
and active points of kidney damage.


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CHAPTER 4: DISCUSSION
4.1. Clinical and subclinical characteristics of children SLE
The mean age of disease onset is: 10,52 ± 2,91 years, the
most common group is over 10 years old (63,2%) (Bảng 3.1). The
disease is predominant in female accounting for 88,8% with female /
male ratio = 7,9/1. This result is appropriate with many domestic and
foreign researches. It shows common disease in puberty girls.
SLE is a chronic autoimmune disease with a diverse clinical
phenotype, varying among individuals, also stage of disease. The
common clinical symptoms of SLE in this study were butterfly rash,

the SLEDAI level at all three times ( Table 3.5).
Relation between antibody concentration and SLEDAI level
At the first time (T0), the median concentration of all
antibodies in the group of patients with strong and very strong
disease activity (SLEDAI> 10) was higher than the group of patients
with mild and moderate disease activity (SLEDAI ≤ 10), the
difference was statistically significant with p 10 was higher than that of patients
with SLEDAI ≤ 10, the difference was statistically significant with p
10 was higher than that of patients with SLEDAI ≤ 10, the
difference was statistically significant with p
We found the ability to predict LN of AnuAb, AC1qAb and
Anti-dsDNA antibodies by ROC curve analysis. The ROC analysis
showed that the area under the curve (AUC) for AnuAb was 0.471,
the AUC for Anti-dsDNA was 0.60, the AUC for AC1qAb was 0.663
(Figure 3.1). Thus, only AC1qAb has value to suggest diagnosis of
LN in SLE. The optimal threshold value for AC1qAb to predict LN is
21.1 U / ml with 44.4% sensitivity and 84.6% specificity. The
majority of authors suggest that aC1q is a useful marker, highly
specific, non-invasive biomarker to diagnose nephritis. Studies with
different results may be due to different samples, serum tests of
different manufacturers. Our diagnostic value of AC1qAb is not high
may be due to the research sample. It is necessary to have a research
design that is more suitable for this purpose.
4.3.2. Relationship between antibody and kidney lesion
In our study, group III and group IV of kidney lesions were
differed in subclinical symptoms of kidney damage. The rate of
increased serum creatinine, decreased GFR, PCU > 200 mg/mmol,
Urinary red blood cells, urinary white blood cells in group IV was
higher than that of group III, the difference was statistically


22
significant p